Dinosaur flatulence may have warmed Earth

Researchers say dinosaur flatulence could have put enough methane into the atmosphere to warm the planet during the hot, wet Mesozoic era.

Sauropod dinosaurs roamed widely around the Earth 150 million years ago, and scientists say that, just like modern-day cattle, their digestion was aided by methane-producing microbes.

"A simple mathematical model suggests that the microbes living in sauropod dinosaurs may have produced enough methane to have an important effect on the Mesozoic climate," Dr Dave Wilkinson of Liverpool John Moores University said in a statement.

"Indeed, our calculations suggest that these dinosaurs could have produced more methane than all modern sources - both natural and man-made - put together."

Methane is a potent greenhouse gas, with as much as 25 times the climate-warming potential as carbon dioxide.

Dr Wilkinson and co-author Graeme Ruxton of the University of St Andrews worked with methane expert Euan Nisbet at the University of London to make an educated guess about the degree to which gaseous emissions from sauropods could have warmed the atmosphere.

Their research has been published in the journal Current Biology.

Calculating methane emissions from modern animals depends only on the total mass of the animals in question. A mid-sized sauropod probably weighed about 20,000 kilos, and there were a few dozen of them per square kilometre, the researchers found.

They reckoned that global methane emissions from sauropods were about 528 million tonnes per year, comparable to all modern methane emissions.

Unlike emissions of carbon dioxide, which come from natural sources but also from the burning of fossil fuels, methane emissions have decreased substantially since the start of the Industrial Revolution some 150 years ago.

Before the fossil-fuel intensive Industrial Revolution took off, methane emissions were roughly 203 million tons annually; modern ruminants, including cows, goats, giraffes and other animals, emit between 50 million and 100 million tons of methane a year.